Plumerias will lose their leaves and go dormant in our temperate climates due to our fluctuating temps and seasonal changes in light levels. Unless your growing area is in the tropics, then they do not go fully leafless.
Your plant is still struggling to wake up. Try to position first in part sun area, ideally morning sun, and wait till it pushes out at least one good leaf. It needs a bit of shade while trying to wake up after it went dormant. Do not water the plant yet, be patient.
Our weather has been cranky this year, and my Plumies also took its time to wake up properly, so it woke up in June, instead of early May.
Patience will be your friend for now.